NMR Quantification of Halogen-Bonding Ability To Evaluate Catalyst Activity
作者:Yun-Pu Chang、Teresa Tang、Jake R. Jagannathan、Nadia Hirbawi、Shaoming Sun、Jonah Brown、Annaliese K. Franz
DOI:10.1021/acs.orglett.0c02427
日期:2020.8.21
Quantification of halogen-bonding abilities is described for a series of benzimidazolium-, imidazolium- and bis(imidazolium) halogen-bond donors (XBDs) using P-31 NMR spectroscopy. The measured Delta delta(P-31) values correlate with calculated activation free energy Delta G(double dagger) and catalytic activity for a Friedel-Crafts indole addition. This rapid method also serves as a sensitive indicator for Bronsted acid impurities.